It’s the first full day of spring and millions will spend it inside watching basketball on TV. So we created a tournament where the real battles happen out in nature. We’ve whittled it down to the “sweet sixteen,” but picking the winners is up to you.

The voting starts on March 28 on The Nature Conservancy’s local Facebook pages (you can find yours here), but you can start getting ready now. Check out the head-to-head matchups — and then before you fill out your bracket, see how this “expert” sees the tournament playing out.

Marine Bracket

The Favorite: Sharks

The Sharks are probably the animal most experts pick to win the whole tournament. But as a Maryland resident it’s my legal obligation to say, “Go Terps!”

Cinderella: Oysters

Oyster reefs protect coastlines from surges and other dangers and a single oyster can filter up to 50 gallons of water a day.

Fun Fact: Hurricanes are not actually animals!

Our Prediction: The best chance to upset the Sharks this early would be a super cuddly animal and we don’t see one here. Sharks advance.

Freshwater Bracket

The Favorite: Gators

Like the Marine region, pure power makes all the difference here. Alligators once had the strongest lab-measured bite of any animal. That’s tough for a salmon to beat.

Our Prediction: Tigers vs. Bears is easily the most competitive first round matchup. Once the Tigers escape that battle they’ll cruise to the Final Four.

Grasslands Bracket

The Favorite: Wolves

You’re not just competing against one wolf, as Alan reminded us in The Hangover, they always travel in packs. It’s hard to imagine a Hawk beating that.

Cinderella: Golden Eagles

According to their Wikipedia page (so it must be true), Golden Eagles have been used in falconry to hunt dangerous prey like Gray Wolves. That could make for an interesting second round matchup.

Fun Fact: Each spring groups of Sage Grouse males gather and perform an elaborate strutting display while the females watch and pick the most attractive males for mating. Basically it’s the plot of Saturday Night Fever.

Our Prediction: Golden Eagles

We’re going with the upset here for two simple reasons: people love birds and they’re used to hunt Wolves!

The Final Four

Sharks over Gators

Tigers over Golden Eagles

The Champion

Beauty and brawn, this is the Tigers tournament to lose.

So, think I got it right or are these the worst predictions you’ve ever seen? Make your predictions in the comments section below!